Correction

We wish to report two corrections to our study [1], neither of which alters the interpretation of the data or the conclusions drawn.
First, we have discovered that the data file from a microarray hybridization (prostate
RNA versus normal genomic DNA) used to derive the plot in Figure 4a became corrupted during data processing. The corrected plot (Figure 4a) displays a stronger correlation between directly and indirectly estimated transcript
levels, indicating even better performance of our method of estimating transcript
abundance. The corrected data file has been deposited to the Stanford Microarray Database
(SMD) and Gene Expression Omnibus (GEO) repositories. Second, we have identified a
'frame-shift' in the Additional data file 2 (Sheet 5) data set; the corrected data
file has been deposited to the supplemental site.